Although not multi-sport, the Upper Deck Comic Ball sets should be mentioned as well. I know at least some of them feature actual baseball and football players, but I think there's a set or two that are solely Looney Tunes characters.
I personally count them all as Looney Tunes cards, and thus they fall into the Movie & TV category of Non-Sports cards, but I know at least some are listed here under sports.
VERY slow trading due to health problems. Not transferrable so safe to trade with, just moving is painful and can't always access the cards.
Cardboard History My COMC
New Collection Website: Cardboard History Gallery (Still under construction)
Tips on how to make your scans look like the card does in hand (No more washed out, fuzzy scans!):
